4.4. Structural peculiarities and environmental input as arboreal adaptations in P. tricuspis skull evolution
Sanger et al (2011) suggested that similar skull modules in morphologically related arboreal species lineages have been found to evolve traits that converge on similar integration patterns as seen in the long-faced anoles (A. carolinensis and A. bahorucoensis ) in the evolution of rostrum specific modules and the short-faced trunk-ground anoles (A. sagrei and A. cybotes ) with no modularity at all. Average asymmetry in the current sample population seemed to be concentrated in rostral areas, the rostral limit of the nasal bone as well as the caudal limit of the parietal bone in the dorsal aspect while the posthion, ventro-lateral sutures of temporal bones and the zygoma represented major asymmetric areas on the ventral side. Considering the heterogeneity of the sampling geographical ecologies; across the rain forest belt and guinea savannah zone this may disallow putative inference on similar skull developmental errors and skull asymmetric components observed (Fig. 5).
Our results on modularity of subsisting and contiguous cranial parts partitioned based on anatomical co relations, embryologic origins suggested a profoundly stronger covariance coefficients for symmetric components for all hypothesis tested but a minimal RV coefficients for asymmetric components (Table 8) as an attestation of a global weakness of skull integration processes in asymmetry of component parts, an observation which has been documented for rodents, reptiles, insects and dogs (Drake and Klingenberg, 2010; Esquerre et al., 2017; Benitez et al., 2020). Landmark partitions based on the fore going resulted in lower co-variation in partitions based on developmental relations comparison to partitions based on anatomical proximities. A combination of three separate embryological compartments were analyzed for dependency but was found to be comparatively weaker to all other tested partitions for dorsal skull landmarks. The reverse was demonstrated in the ventral view for such hypothetical tests. A caveat could be the inadequacy of structural landmarks or limitation of assessable modules to clearly elucidate the boundaries between these partitions.